Rotary retort



1964 H. L. EICHELBERG ETAL 3,

ROTARY RETORT Filed Dec. 6, 1962 3 Sheets-Sheet 1 I I l x: h l l IN E TORS Ham/9r t na-1.55m Row 1- THOMSON BY WW9 Z ATTORNE Filed Dec. 6, 1962 H. L. EICHELBERG ETAL ROTARY RETORT 3 Sheets-Sheet 2 ATTORN Y5 Oct. 13, 1964 Filed Dec. 6, 1962 H. L. EICHELBERG ETAL ROTARY RETORT' 3 Sheets-Sheet 3 INVENTORS ffswar Z. E/Cl/L as ATTO R N EYS United States Patent 3,152,795 RQTARY RETORT Henry L. Eichelherg and Rita L. Thomson, Watertown,

Wis, assignors to Basic Products Corporation, Milwau- Bree, Wis, a corporation of Wisconsin Filed Dec. 6, 1962, Ser. No. 242,844

3 (Ilaims. (Cl. 263-32) This invention relates to apparatus for processing small parts such as needle bearings and the like in load quantities.

There are many applications for an open retort for use in the processing of dense loads of small parts, such as the carburizing of needle bearings, processing small stampings, sintered shapes, small screw machine products, and the like. Loads of such small parts tend to stratify due to improper tumbling or rotation and then cannot be properly treated due to the inability of gases to circulate eifectively around the parts.

The principal object of this invention is to provide apparatus for processing loads of small parts by subjecting them to a preselected atmosphere such that each part is evenly exposed to the atmosphere.

Another object of the invention is to provide such an apparatus that treats the parts in a continuous manner. Still another object of the invention is to provide such an apparatus in which a single retort or multiple retorts can be employed in a single furnace.

Another object of the invention is to provide such an apparatus in which the retort or retorts are charged at one end and discharge the load in a continuous manner from the other end into a quenching bath or the like.

In one aspect of the invention, small parts such as needle bearings or the like may be, but not necessarily, hopper-fed to a conveyor that feeds them into a hollow, cylindrical retort mounted within a gas-tight furnace.

The retort may be mounted within the furnace for rotation about its longitudinal axis which latter may be slightly inclined toward the exit end of the furnace. The furnace may be electrically heated or may be an atmosphere controlled furnace.

In another aspect of the invention, the retort may comprise a relatively thick shell having sufiicient elongated perforations therethrough so that substantially fifty percent of its surface is capable of freely passing gas from the exterior to the interior and vice versa.

In still another aspectof the invention, parallel, longitudinally extending, peripherally spaced rods such as rectangular bars or round shapes may be mounted on the internal peripheral surface of the retort, and they as well as the perforations are arranged so that neither interferes with the other- In still another aspect of the invention, a screen means orthe like may completely cover the inner peripheral surface of the retort to prevent the small parts being Y processed from passing through the elongated perforations in the periphery of the retort.

' radiant tube fired or controlled atmosphere furnace which may include means for providing effective circulation of atmosphere gases through the load of parts within the retort means.

The above, other objects and novel features of the invention will become apparent from the following specification and accompanying drawings which are merely exemplary.

In the drawings:

FIG. 1 is a sectional elevational view of apparatus to which the principles of the invention have been applied;

FIG. 2 is a sectional view taken substantially along line 2-2 of FIG. 1;

FIG. 3 is an enlarged View of part of the apparatus shown in FIG. 1;

FIG. 4 is a sectional view taken substantially along line 4-4 of FIG. 3; and

FIG. 5 is a view similar to that of FIG. 4 but showing a modified form of the retort construction.

Referring to the drawings, and particularly to FIG. 1, the principles of the invention are shown as applied to apparatus including a furnace which may include relatively thick, heateresistant walls 11 which may be made of fire brick or ceramic materials. The furnace 10 may be gas fired through inlet lines 12 and exhaust lines .13; or it may be fired by radiant tube means 14-. Circulating fan means 15' may be provided for distributing the furnace atmosphere uniformly through the furnace.

Transversely spaced standards 16 may be located on the furnace floor and each may support caster means 17 for rotatably supporting a hollow, cylindrical retort 18. The furnace 10 may be mounted on a foundation 19 on adjustable jacks so that it may be inclined downwardly from left to right to facilitate the motion of small workpieces through the retort 18. Referring to FIGS. 3, 4 and 5, the retort 18 may comprise a hollow, relatively thickwalled cylindrical shell, although other than circular cross sectional shapes could be employed.

Longitudinally spaced, peripherally extending rows 19' of elongated apertures 20 may be provided in the cylinder 18 and these apertures 20' preferably .are aligned longitudinally for a purpose to be described. The number and size of the apertures 2% preferably are such that at least about fifty percent of the surface of retort I8 is open to the free ingress and egress of the furnace atmosphere.

Screen means 21 may cover the inner peripheral surface of the retort 18 to permit the passage of atmosphere through the apertures 20' but to prevent the loss therethrough of small parts being processed.

In order to continuously tumble thesmall parts being processed, longitudinally extending rods or bars 22 may be attached to the retort so that they extend along the inner peripheral surface of the retort between the longitudinally aligned rows of apertures 20, providing a corrugated inner peripheral surface of the retort 18. In FIG. 4, the rods 22 are located such that the screen 21 lies between them and the inner periphery of the retort 18. In FIG. 5, the corrugated surface is formed by longitudinally extending, peripherally spaced beads 23 that are integral with the peripheral wall of the retort. They may be cast in the form shown or machined from a thick-walled retort. In FIG. 5, the screen 21 is shown as being located inwardly of the beads 23. e

The retort 18 may rest on the casters 17 within the furnace 1th and may include an integrally connected, hollow charging throat portion 24 that extends through the end wall 11 to the exterior of the furnace 10. The throat portion 24 may include a cylindrical portion 25 that is journaled in a bearing 26 mounted on a bracket 27 fixed to the outer surface of end wall 11. Drive means, which is shown in the form of a V-belt pulley 28, may be fixed to the cylindrical portion 25 for rotating the retort 18 within furnace 10. A seal 29 may be provided about the portion 25 to hermetically seal the interior of furnace 10.

A hopper 30 may include a hollow, cylindrical dis- 3 charge 31 that rotatably receives the end of the cylindrical portion 25. A screw conveyor 32 may be located within the discharge 31 and it may be rotated by a driveincluding a V-belt pulley 33. The conveyor screw 32 may extend into the throat 24 for feeding small parts to be processed from hopper 30 to the retort 18.

Referring to FIG. 2, there may be a plurality of retorts arranged longitudinally in parallel relation within the furnace 10, and their discharge ends may cooperate with a chute 34 that passes through the bottom wall 11 of furnace and may include a hermetical seal between the chute 34 and wall 11. The lower exrernity of chute 34 may discharge below the surface of a quench bath 35 so as to maintain gas-tight the discharge from furnace 10. The processed small parts discharge onto a conveyor belt 36 having one end below the surface of the quenching bath 35, its discharge end above such bath, and arranged to discharge the quenched parts at a location outside the quench bath.

The metal parts of the apparatus previously described that are located within the furnace 10 may be made from a nickel chrome alloy to prevent their deterioration.

Although the various features of the improved apparatus for processing small parts has been shown and described in detail to fully disclose one embodiment of the invention, it will be evident that change may be made in such details and certain features may be used without others without departing from the principles of the invention.

What is claimed is:

1. Apparatus for processing small parts comprising in combination, a furnace adapted to have a controlled atmosphere therein; a retort mounted within said furnace bling of parts contained therein; and means for rotating said retort.

2. Apparatus for processing small parts comprising in combination, a furnace adapted to have a controlled atmosphere therein; a retort mounted within said furnace for rotation about its longitudinal axis, said retort being of a rotatable hollow relatively thick shell of cylindrical construction and including peripherally disposed and longitudinally spaced apertures therein that are adapted to be larger than the parts normally processed therein; a screen lining fixed to the inner periphery of said retort; means providing a corrugated inner peripheral surface on said retort for causing the continuous tumbling of parts contained therein; and means for rotating said retort.

3. Apparatus for processing small parts comprising in combination, a furnace adapted to have a controlled atmosphere therein; a retort mounted within said furnace for rotation about its longitudinal axis, said retort being of a rotatable hollow relatively thick shell of cylindrical construction and including peripherally disposed and longitudinally spaced apertures therein that are adapted to be larger than the parts normally processed therein; a screen lining fixed to the inner periphery of said retort; an entrance throat fixed to said retort and extending through a wall of said furnace; a hopper-fed conveyor having a discharge in communication with said throat; means within said retort for causing the continuous tumbling of parts contained therein; and means for rotating said retort. I

References Cited in the file of this patent UNITED STATES PATENTS 245,930 Smith Aug. 23, 1881 340,677 Perry et a1. -a Apr. 27, 1886 1,294,805 Horst Feb. 18, 1919 1,697,268 Evesmith Jan. 1, 1929 2,265,358 Denning Dec. 9, 1941 2,624,561 Heyn Jan. 6, 1953 3,020,648 Strike Feb. 13, 1962 

1. APPARATUS FOR PROCESSING SMALL PARTS COMPRISING IN COMBINATION, A FURNACE ADAPTED TO HAVE A CONTROLLED ATMOSPHERE THEREIN; A RETORT MOUNTED WITHIN SAID FURNACE FOR ROTATION ABOUT ITS LONGITUDINAL AXIS, SAID RETORT BEING OF A ROTATABLE HOLLOW RELATIVELY THICK SHELL OF CYLINDRICAL CONSTRUCTION AND INCLUDING PERIPHERALLY DISPOSED AND LONGITUDINALLY SPACED APERTURES THEREIN THAT ARE ADAPTED TO BE LARGER THAN THE PARTS NORMALLY PROCESSED THEREIN; 